Control method for storage device controller system, and storage device controller system

ABSTRACT

The present invention provides a control method for a storage device controller system provided with a first storage device controller that is connected to first and second storage devices storing data in the CKD format and the FBA format, respectively, and that has first and second communications control means that receive data input/output requests from a mainframe computer and an open system computer, respectively, and a second storage device that is connected to a third storage device storing data in the CKD format and that has third communications means connected to the second communications means, wherein the first storage device controller transmits a command to the second storage device controller if a data read request received from the open system computer is for data stored on the third storage device, and transmits the data that are read out from the third storage device by the second storage device controller to the open system computer.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application is based on Japanese Patent ApplicationNo. 2002-354842 filed in Japan on Dec. 6, 2002, which is hereinincorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to control methods for storagedevice controller systems and to storage device controller systems.

[0004] 2. Description of the Related Art

[0005] In recent years, computer systems have come to handle extremelylarge amounts of information. Moreover, large amounts of storage datahave accumulated as the result of the long years of operation ofcomputer systems. Thus, the technology of storage consolidation has beendeveloped to effectively utilize these large amounts of storageinformation. Storage consolidation is a technology for coordinating themanagement of storage apparatuses that to date have been operatedseparately for each computer system so as to consolidate and manage thelarge amount of storage information that has been stored separately ineach storage apparatus.

[0006] An example of such a technology relates to a storage apparatusthat can handle a plurality of transfer block sizes for data sent andreceived between the storage apparatus and a computer, allowingcomputers by various manufactures to be connected through a singlestorage apparatus.

[0007] The technology, however, is for a storage device that allows thetransfer block size to be selected when the device is initialized.Consequently, although it allows computers by various manufactures withdifferent transfer block sizes to be connected, the computers by thesemanufactures cannot be combined and operated at the same time.

SUMMARY OF THE INVENTION

[0008] Possible methods for introducing a new storage control deviceinclude a method for completely shifting from operation of the oldstorage control device to only the newly introduced storage controldevice, and a method for operating the old storage control device andthe newly introduced storage device side by side. If shifting between orjointly using storage control devices having an FICON (registeredtrademark) interface for the mainframe, however, it becomes necessary toconvert the recording format within the storage control devices, and itmay be difficult to introduce new storage control devices. This isbecause the data format known as CKD (count key data) that is used bythe mainframe is different from the FBA (fixed block architecture) dataformat that is used in storage control devices, and these two dataformats are converted and controlled within a storage system. Therefore,requests from the mainframe host received by the FICON (registeredtrademark) interface cannot be relayed to other storage control devices.

[0009] If the data of a mainframe computer, with large amounts ofaccumulated data, and the data of open system computers, which havequickly become popular due to the miniaturization of computers in recentyears, are to be shared, then since the data of the mainframe computerand the data of open system computers are stored on storage controldevices in different formats that are not compatible, there arises theneed to transfer data stored on the storage control device to anotherstorage control device prior to sharing, and in particular to a storagecontrol device that is already shared.

[0010] Accordingly, it is a main object of the present invention toprovide a control method for a storage device controller system and astorage device controller system that allow existing storage devices tobe accessed regardless of the computer type.

[0011] A control method for a storage device controller system, whereinthe storage device controller system comprises a first storage devicecontroller having first input/output control means for performinginput/output processing with respect to a first storage device storingdata in accordance with a first recording format, second input/outputcontrol means for performing input/output processing with respect to asecond storage device storing data in accordance with a second recordingformat, first communications control means for receiving datainput/output requests from a first information processing device foraccessing data stored on the first storage device, and secondcommunications control means for receiving data input/output requestsfrom a second information processing device for accessing data stored onthe second storage device, and a second storage device controller havingthird input/output control means for performing input/output processingwith respect to a third storage device storing data in accordance withthe second recording format, and third communications control means forreceiving input/output requests with respect to data stored on the thirdstorage device, and the second communications control means and thethird communications control means are connected, wherein the controlmethod for a storage device controller system comprises a step in whichthe first storage device controller receives a data read request fromthe first information processing device, a step in which the firststorage device controller determines that the data read request is fordata stored on the third storage device, a step in which the firststorage device controller transmits the data read request to the secondstorage device controller if it is determined that the data read requestis for data stored on the third storage device, a step in which thesecond storage device controller reads out data stored on the thirdstorage device and transmits the data to the first storage devicecontroller, and a step in which the first storage device controllertransmits the data to the first information processing device.

[0012] Other problems and methods for solving the same that aredisclosed by the present application will be made clearer through thedescription of the embodiments and the drawings of the presentinvention.

[0013] With the present invention, it is possible to provide a controlmethod for a storage device controller system and a storage devicecontroller system that allow existing storage devices to be accessedregardless of the computer type.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Preferred embodiments of the present invention will now bedescribed in conjunction with the accompanying drawings, in which:

[0015]FIG. 1 is a block diagram showing the overall configuration of thestorage device controller system according to the present embodiment;

[0016]FIG. 2 is a diagram showing the dataset management table accordingto the present embodiment;

[0017]FIG. 3 is a diagram showing the file management table according tothe present embodiment;

[0018]FIG. 4 is a flowchart showing the flow of the operation in a casewhere an open system computer reads the data of a storage volume in theCKD format according to the present embodiment;

[0019]FIG. 5 is a flowchart showing the flow of the operation in a casewhere an open system computer writes data to a storage volume in the CKDformat according to the present embodiment;

[0020]FIG. 6 is a flowchart showing the flow of the operation in a casewhere a mainframe system computer reads the data of a storage volume inthe FBA format according to the present embodiment; and

[0021]FIG. 7 is a flowchart showing the flow of the operation in a casewhere a mainframe system computer writes data to a storage volume in theFBA format according to the present embodiment.

DETAILED DESCRIPTION OF THE INVENTION Overview of the Disclosure

[0022] At least the following matters will be made clear by theexplanation in the present specification.

[0023] A first configuration of the present embodiment is a controlmethod for a storage device controller system, wherein the storagedevice controller system is provided with a first storage devicecontroller having first input/output control means for performinginput/output processing with respect to a first storage device storingdata in accordance with a first recording format, second input/outputcontrol means for performing input/output processing with respect to asecond storage device storing data in accordance with a second recordingformat, first communications control means for receiving datainput/output requests from a first information processing device foraccessing data stored on the first storage device, and secondcommunications control means for receiving data input/output requestsfrom a second information processing device for accessing data stored onthe second storage device, and a second storage device controller havingthird input/output control means for performing input/output processingwith respect to a third storage device storing data in accordance withthe second recording format, and third communications control means forreceiving input/output requests with respect to data stored on the thirdstorage device, and the second communications control means and thethird communications control means are connected, and wherein thecontrol method for a storage device controller system includes a step inwhich the first storage device controller receives a data read requestfrom the first information processing device, a step in which the firststorage device controller determines that the data read request is fordata stored on the third storage device, a step in which the firststorage device controller transmits the data read request to the secondstorage device controller if it is determined that the data read requestis for data stored on the third storage device, a step in which thesecond storage device controller reads out data stored on the thirdstorage device and transmits the data to the first storage devicecontroller, and a step in which the first storage device controllertransmits the data to the first information processing device.

[0024] With this configuration, if a storage device controller is newlyintroduced to existing storage device controllers, for example, then theinformation stored on the old storage device controllers can be read viathe new storage device controller regardless of the recording format ofthe data of the old storage device controllers. Here, the informationstored on the old storage device controllers can be read out via the newstorage device controller without altering the specifications ormodifying the old storage device controllers or transferring the datastored on the storage device controllers, for example.

[0025] A further configuration of the present embodiment is a controlmethod for a storage device controller system, wherein the storagedevice controller system is provided with a first storage devicecontroller having first input/output control means for performinginput/output processing with respect to a first storage device storingdata in accordance with a first recording format, second input/outputcontrol means for performing input/output processing with respect to asecond storage device storing data in accordance with a second recordingformat, first communications control means for receiving datainput/output requests from a first information processing device foraccessing data stored on the first storage device, and secondcommunications control means for receiving data input/output requestsfrom a second information processing device for accessing data stored onthe second storage device, and a second storage device controller havingthird input/output control means for performing input/output processingwith respect to a third storage device storing data in accordance withthe second recording format, and third communications control means forreceiving input/output requests with respect to data stored on the thirdstorage device, wherein the second communications control means and thethird communications control means are connected, and the control methodfor a storage device controller system includes a step in which thefirst storage device controller receives a data write request from thefirst information processing device, a step in which the first storagedevice controller determines that the data write request is for thethird storage device, a step in which the first storage devicecontroller transmits the data write request to the second storage devicecontroller if it is determined that the data write request is for thethird storage device, a step in which the first storage devicecontroller transmits write data received from the first informationprocessing device to the second storage device controller, and a step inwhich the second storage device controller writes the write data to thethird storage device.

[0026] With this configuration, if a storage device controller is newlyintroduced to existing storage device controllers, for example, thendata can be written to the old storage device controllers through thenew storage device controller regardless of the recording format of thedata of the old storage device controllers. Here, data can be written tothe old storage device controllers through the new storage devicecontroller without altering the specifications or modifying the oldstorage device controllers or transferring the data stored on thestorage device controllers, for example.

[0027] In a further configuration of the present embodiment, in thecontrol method for a storage device controller system, the step in whichthe first storage device controller transmits the data to the firstinformation processing device has a step in which the first storagedevice controller transmits the data to the first information processingdevice after converting them to data in accordance with the firstrecording format.

[0028] With this configuration, if information stored on the secondstorage device controller is read out via the first storage devicecontroller, the first storage device controller performs conversion ofthe recording format, and thus it is no longer necessary for the firstinformation processing device to perform such conversion of therecording format.

[0029] In a further configuration of the present embodiment, in thecontrol method for a storage device controller system, the step in whichthe first storage device controller transmits write data received fromthe first information processing device to the second storage devicecontroller has a step in which the first storage device controllertransmits the write data received from the first information storagedevice to the second storage device controller after converting them todata in accordance with the second recording format.

[0030] With this configuration, if information is to be written to thesecond storage device controller via the first storage devicecontroller, then the first storage device controller performs conversionof the recording format, and thus it is no longer necessary for thefirst information processing device to perform such conversion of therecording format.

[0031] In a further configuration of the present embodiment, in thecontrol method for a storage device controller system, the first and thesecond recording formats are the FBA format and the CKD format,respectively.

[0032] With this configuration, it is possible to access data stored ona storage device controller storing data in the CKD format from an opensystem computer storing data in the FBA format.

[0033] In a further configuration of the present embodiment, in thecontrol method for a storage device controller system, the first and thesecond recording formats are the CKD format and the FBA format,respectively.

[0034] With this configuration, it is possible to access data stored ona storage device controller storing data in the FBA format from amainframe computer storing data in the CKD format.

[0035] A further configuration of the present embodiment is a storagedevice controller system that comprises a first storage devicecontroller having first input/output control means for performinginput/output processing with respect to a first storage device storingdata in accordance with a first recording format, second input/outputcontrol means for performing input/output processing with respect to asecond storage device storing data in accordance with a second recordingformat, first communications control means for receiving datainput/output requests from a first information processing device foraccessing data stored on the first storage device, and secondcommunications control means for receiving data input/output requestsfrom a second information processing device for accessing data stored onthe second storage device, and a second storage device controller havingthird input/output control means for performing input/output processingwith respect to a third storage device storing data in accordance withthe second recording format, and third communications control means forreceiving input/output requests with respect to data stored on the thirdstorage device, and the second communications control means and thethird communications control means are connected, wherein the firststorage device controller comprises means for receiving a data readrequest from the first information processing device, means fordetermining that the data read request is for data stored on the thirdstorage device, means for transmitting the data read request to thesecond storage device controller if it is determined that the data readrequest is for data stored on the third storage device, and means fortransmitting to the first information processing device the data storedon the third storage device that are transmitted from the second storagedevice controller, and the second storage device controller comprisesmeans for reading out data stored on the third storage device andtransmitting the data to the first storage device controller due to thedata read request that is transmitted from the first storage devicecontroller.

[0036] A further configuration of the present embodiment is a storagedevice controller system that comprises a first storage devicecontroller having first input/output control means for performinginput/output processing with respect to a first storage device storingdata in accordance with a first recording format, second input/outputcontrol means for performing input/output processing with respect to asecond storage device storing data in accordance with a second recordingformat, first communications control means for receiving datainput/output requests from a first information processing device foraccessing data stored on the first storage device, and secondcommunications control means for receiving data input/output requestsfrom a second information processing device for accessing data stored onthe second storage device, and a second storage device controller havingthird input/output control means for performing input/output processingwith respect to a third storage device storing data in accordance withthe second recording format, and third communications control means forreceiving input/output requests with respect to data stored on the thirdstorage device, and the second communications control means and thethird communications control means are connected, wherein the firststorage device controller comprises means for receiving a data writerequest from the first information processing device, means fordetermining that the data write request is for the third storage device,means for transmitting the data write request to the second storagedevice controller if it is determined that the data write request is forthe third storage device, and means for transmitting write data that arereceived from the first information processing device to the secondstorage device controller, and the second storage device controllercomprises means for writing the write data to the third storage device.

[0037] Another configuration of the present embodiment relates to thefirst storage device controller in the storage device controller system.

[0038] A further configuration of the present invention relates to aprogram for executing the above functions on the first storage devicecontroller of the storage device controller system.

Example of the Overall Configuration

[0039] Hereinafter, embodiments of the present invention will bedescribed in detail using the drawings.

[0040] First, FIG. 1 shows a block diagram of the overall configurationof the storage device controller system according to this embodiment.

[0041] A mainframe computer 100 is a computer (information processingdevice) provided with a CPU (central processing unit) and a memory, forexample. The mainframe computer 100 is connected to a control terminal(not shown), and receives commands from the control terminal andexecutes predetermined programs. For example, it may be used as thecentral computer of a large-scale computer system, such as an automaticteller system of a bank or an airplane seat reservation system. Amainframe system application program 101 is executed on the mainframecomputer 100 under the control of a mainframe system operating system103.

[0042] On the other hand, an open system computer 200 is also a computer(information processing device) provided with a CPU and a memory, forexample. The open system computer 200 is manufactured according topublicly known technical standards, and is characterized in that as longas the standard matches, devices from different manufacturers can beconnected to it and used. Also, the reduction in size of computers inrecent years has led to tasks that were conventionally carried out onthe mainframe computer 100 to be carried out on the open system computer200. An open system application program 201 is executed on the opensystem computer 200 under the control of an open system operating system203.

[0043] The mainframe computer 100 and the open system computer 200 areboth connected to a first storage device controller 300. The firststorage device controller 300 is provided with a first mainframe systemvolume (storage device) 360 and a first open system volume (storagedevice) 370, which store the data of the mainframe computer 100 and theopen system computer 200, respectively.

[0044] The mainframe computer 100 traditionally stores data in the CKD(count key data) format on the first mainframe system volume 360. In theCKD format, the data storage address is designated by the cylindernumber, the head number, and the record number. On the other hand, theopen system computer 200 stores data in the FBA (fixed blockarchitecture) format on the first open system volume 370. In the FBAformat, the data storage address is designated by the LBA (logical blockaddress).

[0045] Consequently, the mainframe computer 100 cannot directly accessdata stored on the first open system volume 370 and the open systemcomputer 200 cannot directly access data stored on the fist mainframesystem volume 360.

[0046] To access data stored on the first open system volume 370 fromthe mainframe computer 100, it is necessary to make the data stored inthe FBA format able to be treated as data in the CKD format. Anopen-system data access program 102 that is executed on the mainframecomputer 100 is a program for allowing data stored in the FBA format onthe first open system volume 370 to be accessed from the mainframecomputer 100. The mainframe system application program 101 can accessdata stored in the FBA format by carrying out data access via the opensystem data access program 102.

[0047] At the same time, to access data stored on the first mainframesystem volume 360 from the open system computer 200, it is necessary tomake the data stored in the CKD format able to be treated as data in theFBA format. By carrying out data access via a mainframe system dataaccess program 202 that is executed on the open system computer 200, theopen system application program 201 can access data stored in the CKDformat.

[0048] With the technology described above, the first mainframe systemvolume 360 storing data in the CKD format and the first open systemvolume 370 storing data in the FBA format can be accessed from both themainframe computer 100 and the open system computer 200, which areconnected to the fist storage device controller 300.

[0049] A storage device controller system according to the presentembodiment is described below.

First Storage Device Controller

[0050] As mentioned above, the first storage device controller 300 isconnected to the mainframe computer 100 and the open system computer200. The first mainframe system volume 360 storing data in the CKDformat and the first open system volume 370 storing data in the FBAformat can be accessed from either computer.

[0051] A channel controller (communications control means) A 310 isconnected to the mainframe computer 100 and sends and receives datainput/output commands and controls the input and output of data. Aprocessor A 311 is in charge of the control of the channel controller A310. A cache memory A 312 temporarily stores data that are sent andreceived between it and the mainframe computer 100. A control memory A313 stores a control program A 318 for performing control of theprocessor A 311 and a dataset management table 317. One communicationsinterface A 314 is connected to the mainframe computer 100 and anothercommunications interface A 314 is connected to a second storage devicecontroller 400. A disk interface A 315 is connected to a disk controller(input/output control means) A 340, a disk controller B 350, and achannel controller B 320 via an internal network 330.

[0052] The channel controller B 320 is connected to the open systemcomputer 200 and sends and receives data input/output commands andcontrols the input and output of data. A processor B 321 is in charge ofcontrol of the channel controller B 320. A cache memory B 322temporarily stores data sent and received between it and the open systemcomputer 200. A control memory B 323 stores a control program B 328 forperforming control of the processor B 321 and a file management table327. One communications interface B 324 is connected to the open systemcomputer 200 and another communications interface B 324 is connected toa third storage device controller 500. A disk interface B 325 isconnected to the disk controller A 340, the disk controller B 350, andthe channel controller A 310 via the internal network 330.

[0053] The internal network 330 connects the channel controller A 310,the channel controller B 320, the disk controller A 340, and the diskcontroller B 350 to one another.

[0054] The disk controller A 340 receives an instruction from thechannel controller A 310 or the channel controller B 320, and controlsthe input and output of data stored on the first mainframe system volume360 in the CKD format.

[0055] The disk controller B 350 receives an instruction from thechannel controller A 310 or the channel controller B 320, and controlsthe input and output of data stored on the first open system volume 370in the FBA format.

[0056] The first mainframe system volume 360 stores data in the CKDformat. It can be a storage region that is logically structured on aphysical storage region, but it can also be a physical storage region.Also, the first mainframe system volume 360 can be a single unit or aplurality of units. Furthermore, to increase the data reliability andthe high-speed access properties, it can be configured as a RAID(redundant arrays of inexpensive disks).

[0057] The first open system volume 370 stores data in the FBA format.It can be a storage region that is logically structured on a physicalstorage region, but it can also be a physical storage region. Also, thefirst open system volume 370 can be a single unit or a plurality ofunits. Furthermore, to increase the data reliability and the high-speedaccess properties, it can be configured as a RAID.

[0058] It should be noted that as another example of the configurationof the first storage device controller 300, it is possible to adopt aconfiguration in which the data in the CKD 30 format are converted intothe FBA format at the channel controller

[0059] A(310) or the disk controller A(340), so that on the firstmainframe system volume 360 they are converted to the FBA format. Inthis case, data on the first mainframe system volume 360 are notintended for data readout from the open system computer 200, and sincestoring data in the CKD format as they are in that format is requiredfor performance, the fact that they must be accessed via the open systemdata access program 102, for example, is the same.

Second Storage Device Controller

[0060] The second storage device controller 400 is provided with achannel controller C 410, a disk controller C 420, and a secondmainframe system volume 430. It can also be provided with an internalnetwork like the first storage device controller 300.

[0061] The second storage device controller 400 is different from thefirst storage device controller 300 in that it is not provided with anopen system volume for storing data in the FBA format.

[0062] The channel controller C 410 is connected to the first storagedevice controller 300 and sends and receives data input/output commandsand controls the input and output of data. A processor C 411 is incharge of control of the channel controller C 410. A cache memory C 412temporarily stores data sent and received between it and the firststorage device controller 300. A control memory C 413 stores a controlprogram B 328 for performing control of the processor C 411. Acommunications interface C 414 is connected to the first storage devicecontroller 300. A disk interface C 415 is connected to the diskcontroller C 420.

[0063] The disk controller C 420 receives commands from the channelcontroller C 410 and accesses data stored in the CKD format on thesecond mainframe system volume 430.

[0064] The second mainframe system volume 430 stores data in the CKDformat. It can be a storage region that is logically structured on aphysical storage region, but it can also be a physical storage region.Also, the second mainframe system volume 430 can be a single unit or aplurality of units. Furthermore, to increase the data reliability andthe high-speed access properties, it can be configured as a RAID.

Third Storage Device Controller

[0065] The third storage device controller 500 is provided with achannel controller D 510, a disk controller D 520, and a second opensystem volume 530. It can also be provided with an internal network likethe first storage device controller 300.

[0066] The third storage device controller 500 is different from thefirst storage device controller 300 in that it is not provided with amainframe system volume for storing data in the CKD format.

[0067] The channel controller D 510 is connected to the first storagedevice controller 300 and sends and receives data input/output commandsand controls the input and output of data. A processor D 511 is incharge of control of the channel controller D 510. A cache memory D 512temporarily stores data sent and received between it and the firststorage device controller 300. A control memory D 513 stores a controlprogram for performing control of the processor D 511. A communicationsinterface D 514 is connected to the first storage device controller 300.A disk interface D 515 is connected to the disk controller D 520.

[0068] The disk controller D 520 receives commands from the channelcontroller D 510 and accesses data stored in the FBA format on thesecond open system volume 530.

[0069] The second open system volume 530 stores data in the FBA format.It can be a storage region that is logically structured on a physicalstorage region, but it can also be a physical storage region. Also, thesecond open system volume 530 can be a single unit or a plurality ofunits. Furthermore, to increase the data reliability and the high-speedaccess properties, it can be configured as a RAID.

[0070] One possibility as the second storage device controller 400 andthe third storage device controller 500 is a storage device controllerfor a computer system operating in a large-scale computer center, forexample. Huge amounts of storage information have accumulated in suchstorage device controllers as the result of the operation of computersover many years. On the other hand, the introduction of newlarge-capacity storage device controllers is necessary to keep pace withthe breakneck speed of technological advances and the explosive increasein the amount of information that is handled. In this case, although itis possible to completely replace the storage device controller, toallow past storage information from not only the mainframe computer butalso from open-computers to be utilized necessitates that the data aretransferred over to the new storage device controller.

[0071] With the storage device controller according to the presentembodiment, the mainframe computer 100 and the open system computer 200can both access data stored on conventional storage device controllers(the second storage device controller 400 and the third storage devicecontroller 500) via a new storage device controller (first storagedevice controller 300). Moreover, the mainframe computer 100 can alsoaccess data stored on the third storage device controller 500, whichconventionally it could not access. Also, the open system computer 200can also access data stored on the second storage device controller 400,which conventionally it could not access.

[0072] The flow of the operation in a case where data stored on thesecond mainframe system volume 430 of the second storage devicecontroller 400 are accessed from the open system computer 200 isdescribed below according to the flowchart of FIG. 4.

Data Read Operation

[0073] If a dataset stored on a mainframe system volume (the firstmainframe system volume 360 or the second mainframe system volume 430)is to be read, then the open system application program 201 designatesthe dataset name and issues a read command to the mainframe system dataaccess program 202 (S1000). Then, the mainframe system data accessprogram 202 designates the dataset and issues a read command to thechannel controller B 320 connected to the open system computer 200 via adata transfer route B205 (S1001).

[0074] The transfer of data between the open system computer 200 and thechannel controller B 320 via the data transfer route B205 can be carriedout according to a variety of protocols. For example, it is possible toadopt a fiber channel protocol, SCSI (small computer systems interface)protocol, or ISCSI (internet small computer systems interface) protocol,for example. It is also possible to provide several relay nodes orswitches on the data transfer route B205.

[0075] When the channel controller B 320 receives the data read command,the processor B 321 analyzes that data read command and determines thatthe data read command is for a dataset that is stored in the CKD format(S1002). The data read command is then transferred to the channelcontroller A 310 via the internal network 330 (S1003). When the channelcontroller A 310 receives the data read command, the processor A 311references the dataset management table 317 stored on the control memoryA 313 (S1004).

[0076]FIG. 2 shows the configuration of the dataset management table317. The dataset management table 317 is a table for managing thestorage location of data stored on the first mainframe system volume 360and the second mainframe system volume 430 for each dataset.

[0077] A dataset name 610 indicates the dataset name of the data. Avolume number 620 indicates the number of the storage volume in whichthe dataset is stored. A volume location 630 indicates the number of thestorage device controller storing the storage volume. A data location640 indicates the address at which the dataset is stored. If the dataare in the CKD format, a cylinder number 641, a head number 642, and arecord number 643 designate the data storage location.

[0078] When the processor A 311 references the dataset management table317, the storage location of the dataset designated by the data readcommand received from the channel controller B 320 is determined(S1004). If the dataset is stored on the first mainframe system volume360 (S1005), then the processor A 311 issues a dataset read command tothe disk controller A 340 (S1006, S1007).

[0079] On the other hand, if the dataset is stored on the secondmainframe system volume 430 (S1005), then the processor A 311 transfersthe data read command that is received from the channel controller B 320to the second storage device controller 400 via a data transfer route C417 (S1008).

[0080] The protocol for transferring data over the data transfer route C417 is in accordance with the second storage device controller 400.Representative examples of protocols that may be adopted include ESCON(registered trademark) and FICON (registered trademark). Of course, likewith an open system, it is possible to adopt a fiber channel protocol,SCSI protocol, or ISCSI protocol, for example.

[0081] After receiving the data read command, the second device controldevice 400 reads the dataset from the designated address of the secondmainframe system volume 430 via the disk controller C 420 (S1009). Then,the data that are read out are transferred to the first storage devicecontroller 300 over the data transfer route C 417 (S1010).

[0082] The processor A 311 of the channel controller A 310 transfersthose data to the channel controller B 320 via the internal network 330(S1011). Then, the processor B 321 of the channel controller B320transmits the data to the mainframe system data access program 202 overthe data transfer route B205 (S1012).

[0083] The mainframe system data access program 202 converts the datafrom the CKD format to the FBA format and delivers them to the opensystem application program 201 (S1013, S1014). Here, it is also possibleto make the channel controller B 320 perform the conversion of the readout data from the CKD format to the FBA format.

[0084] In this way, it is possible to perform the read out of datastored on the first mainframe system volume 360 or the second mainframesystem volume 430 from the open system computer 200.

Data Write Operation

[0085] Next, the operation in a case where data are written to the firstmainframe system volume 360 or the second mainframe system volume 430from the open system computer 200 is described according to theflowchart of FIG. 5.

[0086] First, the open system application program 201 designates thedataset name and sends the write data and a write command to themainframe system data access program 202 (S2000). The mainframe systemdata access program 202 then converts the data from the FBA format tothe CKD format (S2001). Then, over the data transfer route B205, themainframe system data access program 202 sends the write data and awrite command designating the dataset name to the channel controller B320 connected to the open system computer 200 (S2002).

[0087] When the channel controller B 320 receives the write data and thedata write command, the processor B 321 analyzes the data write commandand determines that the data write command is for a dataset stored inthe CKD format (S2003). Then, the data and the data write command aretransferred to the channel controller A 310 via the internal network 330(S2004). When the channel controller A 310 receives the write data andthe data write command, the processor A 311 references the datasetmanagement table 317 stored on the control memory A 313 and specifiesthe storage location of the dataset (S2005). If the storage location ofthe dataset is the first mainframe system volume 360 (S2006), then theprocessor A 311 sends the write data and the write command to the diskcontroller A 340 (S2007, S2008).

[0088] On the other hand, if the storage location of the dataset is thesecond mainframe system volume 430 (S2006), then the processor A 311transfers the write data and the write command that are received fromthe channel controller B 320 to the second storage device controller 400over the data transfer route C 417 (S2009).

[0089] The second storage device controller 400 that has received thewrite data and the data write command writes the write data to thedesignated address of the second mainframe system volume 430 via thedisk controller C 420 (S2010).

[0090] Thus, it is possible to carry out the writing of data to thefirst mainframe system volume 360 or the second mainframe system volume430 from the open system computer 200. It should be noted that thechannel controller B 320 can also be made to carry out the conversion ofthe write data from the FBA format to the CKD format.

Data Read Operation

[0091] Next, the flow of the operation in a case where data stored onthe second open system volume 530 of the third storage device controller500 are accessed from the mainframe computer 100 is described below inaccordance with the flowchart of FIG. 6.

[0092] If a file stored on an open system volume (the first open systemvolume 370 or the second open system volume 530) is to be read, then themainframe system application program 101 designates the file name andissues a read command to the open system data access program 102(S3000). Then, the open system data access program 102 issues a readcommand, designating the file name, to the channel controller A 310connected to the mainframe computer 100 via a data transfer route A105(S3001).

[0093] The transfer of data between the mainframe computer 100 and thechannel controller A 310 via the data transfer route A105 can be carriedout in accordance with various protocols. For example, it is possible toadopt ESCON (registered trademark) or FICON (registered trademark), forexample. It is also possible to provide several relay nodes or switcheson the data transfer route A105.

[0094] When the channel controller A 310 receives the data read command,the processor A 311 analyzes that data read command and determines thatthe data read command is for a file that is stored in the FBA format(S3002). The data read command is then transferred to the channelcontroller B 320 via the internal network 330 (S3003). When the channelcontroller B 320 receives the data read command, the processor B 321references the file management table 327 stored on the control memory B323 (S3004).

[0095]FIG. 3 shows the configuration of the file management table 327.The file management table 327 is a table for managing the storagelocation of data stored on the first open system volume 370 and thesecond open system volume 530 for each file.

[0096] A file name 710 shows the file name of the data. A volume number720 shows the number of the storage volume in which the file is stored.A volume location 730 shows the number of the storage device controllerstoring the storage volume. A data location 740 shows the address atwhich the file is stored. If the file is in the FBA format, the datastorage location is designated by the LBA, and therefore the value ofthe LBA is entered.

[0097] When the processor B 321 references the file management table327, the storage location of the file designated by the data readcommand received from the channel controller A 310 is determined(S3004). If the file is stored on the first open system volume 370(S3005), then the processor B 321 issues a file read command to the diskcontroller B 350 (S3006, S3007).

[0098] On the other hand, if the file is stored on the second opensystem volume 530 (S3005), then the processor B 321 transfers the dataread command that is received from the channel controller A 310 to thethird storage device controller 500 via a data transfer route C517(S3008).

[0099] The protocol for transferring data over the data transfer routeC517 is in accordance with the third storage device controller 500.Examples of representative protocols include a fiber channel protocol, aSCSI protocol, or an ISCSI protocol.

[0100] After receiving the data read command, the third device controldevice 500 reads the file from the designated address of the second opensystem volume 530 via the disk controller D 520 (S3009). Then, the datathat are read out are transferred to the first storage device controller300 over the data transfer route C517 (S3010).

[0101] The processor B 321 of the channel controller B 320 transfers thedata to the channel controller A 310 via the internal network 330(S3011). Then, the processor A 311 of the channel controller A 310transmits the data to the open system data access program 102 over thedata transfer route A105 (S3012).

[0102] The open system data access program 102 converts the data fromthe FBA format to the CKD format and delivers them to the mainframesystem application program 101 (S3013, S3014). Here, it is also possibleto make the channel controller A 310 perform the conversion from the FBAformat to the CKD format of the read out data.

[0103] In this way, it is possible to carry out the read out of datastored on the first open system volume 370 or the second open systemvolume 530 from the mainframe system computer 100.

Data Write Operation

[0104] Next, the operation in a case where data are written to the firstopen system volume 370 or the second open system volume 530 from themainframe system computer 100 is described according to the flowchart ofFIG. 7.

[0105] First, the mainframe system application program 101 designatesthe file name and sends the write data and a write command to the opensystem data access program 102 (S4000). The open system data accessprogram 102 then converts the data from the CKD format to the FBA format(S4001). Then, over the data transfer route A105, the open system dataaccess program 102 sends the write data and a write command designatingthe file name to the channel controller A 310 connected to the mainframecomputer 100 (S4002).

[0106] When the channel controller A 310 receives the write data and thedata write command, the processor A 311 analyzes the data write commandand determines that the data write command is for a file stored in theFBA format (S4003). Then, the data and the data write command aretransferred to the channel controller B 320 via the internal network 330(S4004).

[0107] When the channel controller B 320 receives the write data and thedata write command, the processor B 321 references the file managementtable 327 stored on the control memory B 323 and specifies the storagelocation of the file (S4005). If the storage location of the file is thefirst open system volume 370 (S4006), then the processor B 321 sends thewrite data and the write command to the disk controller B 350 (S4007,S4008).

[0108] On the other hand, if the storage location of the file is thesecond open system volume 530 (S4006), then the processor B 321transfers the write data and the write command that are received fromthe channel controller A 310 to the third storage device controller 500over the data transfer route D 517 (S4009).

[0109] The third storage device controller 500 that has received thewrite data and the data write command writes the write data to thedesignated address of the second open system volume 530 via the diskcontroller D 520 (S4010).

[0110] Thus, it is possible to carry out the writing of data to thefirst open system volume 370 or the second open system volume 530 fromthe mainframe computer 100. It should be noted that the channelcontroller A 310 may also carry out the conversion of the write datafrom the CKD format to the FBA format.

Other Configuration Examples

[0111] In the example configuration shown in FIG. 1, the first storagedevice controller was connected to the second storage device controllerand the third storage device controller. However, it is also possible toadopt a configuration in which it is connected to only either the secondstorage device controller or the third storage device controller.

[0112] Also, in the example configuration shown in FIG. 1, the secondstorage device controller has only a storage volume that can be accessedin the CKD format and the third storage device controller has only astorage volume that can be accessed in the FBA format. However, it isalso possible to adopt a configuration in which both or only one of thesecond storage device controller and the third storage devicecontroller, like the first storage device controller, have a storagevolume that can be accessed in the FBA format and a storage volume thatcan be accessed in the CKD format.

[0113] Moreover, in the example configuration shown in FIG. 1, the firststorage device controller has a storage volume that can be accessed inthe FBA format and a storage volume that can be accessed in the CKDformat; however, it is also possible to adopt a configuration in whichit has only a storage volume that can be accessed in one of these twoformats.

[0114] Furthermore, the present embodiment was described using the CKDformat and the FBA format as examples. However, other recording formatscan also be adopted.

[0115] Although a preferred embodiment has been described above, theforegoing embodiment is for elucidating the present invention and is notto be construed as limiting the present invention. The present inventioncan be altered and improved without departing from gist thereof, andincludes functional equivalents.

What is claimed is:
 1. A control method for a storage device controllersystem, the storage device controller system comprising: a first storagedevice controller having first input/output control means for performinginput/output processing with respect to a first storage device storingdata in accordance with a first recording format, second input/outputcontrol means for performing input/output processing with respect to asecond storage device storing data in accordance with a second recordingformat, first communications control means for receiving datainput/output requests from a first information processing device foraccessing data stored on said first storage device, and secondcommunications control means for receiving data input/output requestsfrom a second information processing device for accessing data stored onsaid second storage device; and a second storage device controllerhaving third input/output control means for performing input/outputprocessing with respect to a third storage device storing data inaccordance with said second recording format, and third communicationscontrol means for receiving input/output requests with respect to datastored on said third storage device; wherein said second communicationscontrol means and said third communications control means are connected;said control method comprising: a step in which said first storagedevice controller receives a data read request from said firstinformation processing device; a step in which said first storage devicecontroller determines that said data read request is for data stored onsaid third storage device; a step in which said first storage devicecontroller transmits said data read request to said second storagedevice controller if it is determined that said data read request is fordata stored on the third storage device; a step in which said secondstorage device controller reads out data stored on said third storagedevice and transmits said data to the first storage device controller;and a step in which said first storage device controller transmits saiddata to said first information processing device.
 2. A control methodfor a storage device controller system according to claim 1, wherein thestep in which said first storage device controller transmits said datato said first information processing device is a step in which saidfirst storage device controller transmits said data to said firstinformation processing device after converting them to data according tosaid first recording format.
 3. A control method for a storage devicecontroller system according to claim 1, wherein said first and saidsecond recording formats are FBA format and CKD format, respectively. 4.A control method for a storage device controller system according toclaim 1, wherein said first and said second recording formats are CKDformat and FBA format, respectively.
 5. A control method for a storagedevice controller system, the storage device controller systemcomprising: a first storage device controller having first input/outputcontrol means for performing input/output processing with respect to afirst storage device storing data in accordance with a first recordingformat, second input/output control means for performing input/outputprocessing with respect to a second storage device storing data inaccordance with a second recording format, first communications controlmeans for receiving data input/output requests from a first informationprocessing device for accessing data stored on said first storagedevice, and second communications control means for receiving datainput/output requests from a second information processing device foraccessing data stored on said second storage device; and a secondstorage device controller having third input/output control means forperforming input/output processing with respect to a third storagedevice storing data in accordance with said second recording format, andthird communications control means for receiving input/output requestswith respect to data stored on said third storage device; wherein saidsecond communications control means and said third communicationscontrol means are connected; said control method comprising: a step inwhich said first storage device controller receives a data write requestfrom said first information processing device; a step in which saidfirst storage device controller determines that said data write requestis for said third storage device; a step in which said first storagedevice controller transmits said data write request to said secondstorage device controller if it is determined that said data writerequest is for said third storage device; a step in which said firststorage device controller transmits write data received from said firstinformation processing device to said second storage device controller;and a step in which said second storage device controller writes saidwrite data to said third storage device.
 6. A control method for astorage device controller system according to claim 5, wherein the stepin which said first storage device controller transmits write datareceived from said first information processing device to said secondstorage device controller is a step in which said first storage devicecontroller transmits write data received from said first informationstorage device to said second storage device controller after convertingthem to data in accordance with said second recording format.
 7. Acontrol method for a storage device controller system according to claim5, wherein said first and said second recording formats are FBA formatand CKD format, respectively.
 8. A control method for a storage devicecontroller system according to claim 5, wherein said first and saidsecond recording formats are CKD format and FBA format, respectively. 9.A storage device controller system comprising: a first storage devicecontroller having first input/output control means for performinginput/output processing with respect to a first storage device storingdata in accordance with a first recording format, second input/outputcontrol means for performing input/output processing with respect to asecond storage device storing data in accordance with a second recordingformat, first communications control means for receiving datainput/output requests from a first information processing device foraccessing data stored on said first storage device, and secondcommunications control means for receiving data input/output requestsfrom a second information processing device for accessing data stored onsaid second storage device; and a second storage device controllerhaving third input/output control means for performing input/outputprocessing with respect to a third storage device storing data inaccordance with said second recording format, and third communicationscontrol means for receiving input/output requests with respect to datastored on said third storage device; wherein said second communicationscontrol means and said third communications control means are connected;wherein said first storage device controller comprises: means forreceiving a data read request from said first information processingdevice; means for determining that said data read request is for datastored on said third storage device; means for transmitting said dataread request to said second storage device controller if it isdetermined that said data read request is for data stored on said thirdstorage device; and means for transmitting to said first informationprocessing device said data stored on said third storage device that aretransmitted from said second storage device controller; and wherein saidsecond storage device controller comprises: means for reading out datastored on said third storage device and transmitting said data to saidfirst storage device controller based on said data read request that istransmitted from said first storage device controller.
 10. A storagedevice controller system according to claim 9, wherein said means fortransmitting to said first information processing device said datastored on said third storage device that are transmitted from saidsecond storage device controller are means for converting data stored onsaid third storage device that are transmitted from said second storagedevice into data in accordance with said first recording format and thentransmitting them to said first information processing device.
 11. Astorage device controller system according to claim 9, wherein saidfirst and said second recording formats are FBA format and CKD format,respectively.
 12. A storage device controller system according to claim9, wherein said first and said second recording formats are CKD formatand FBA format, respectively.
 13. A storage device controller systemaccording to claim 9, wherein said first storage device controllercomprises: means for receiving a data write request from said firstinformation processing device; means for determining that said datawrite request is for said third storage device; means for transmittingsaid data write request to said second storage device controller if itis determined that said data write request is for said third storagedevice; and means for transmitting write data that are received fromsaid first information processing device to said second storage devicecontroller; and wherein said second storage device controller comprises:means for writing said write data to said third storage device.
 14. Astorage device controller system according to claim 13, wherein saidmeans for transmitting write data that are received from said firstinformation processing device to said second storage device controllerare means for converting write data received from said first informationprocessing device into data in accordance with said second recordingformat and then transmitting them to said second storage devicecontroller.
 15. A storage device controller system according to claim13, wherein said first and said second recording formats are FBA formatand CKD format, respectively.
 16. A storage device controller systemaccording to claim 13, wherein said first and said second recordingformats are CKD format and FBA format, respectively.